(1) Field of the Invention
This invention relates to a versatile maskless patterning system with capability for: selecting rapidly among a plurality of projection lenses, providing multiple resolutions, enabling optimization of the combination of the imaging resolution and exposure throughput, and making possible cost-effective fabrication of microelectronics packaging products.
(2) Description of Related Art
Microelectronic packaging technology is a key driver leading to advancements in the performance of electronic systems that are integrated on circuit boards. Especially for high-processing-power systems, the packages may be the most crucial factor since they gate the rate of communication between different chips, and in fact, a high-end processor may be only as good as the packages that are used to interface it with the other components on the board. Additionally, given the importance of portability for commercial, but especially for all types of military systems, the size of the package is important as well. Recent trends in packaging technology have resulted in small, high-performance packages by means of designs having fine linewidths, multi-level circuitry, and solder-bump interfaces to the circuit board. Fabrication of packages having these advanced design features can be performed only with high-resolution patterning systems that have fine-alignment capability—resolutions down to 10 μm and alignment capability better than 3 μm are required for next-generation microelectronic packages.
While microelectronics packages have traditionally been fabricated by means of conventional lithography tools such as contact printers, the requirements for higher resolution and finer alignment for the multiple layers of the package have led to the need for a mix-and-match approach, based on contact printing, proximity printing, direct-write, as well as projection lithography. The large-area seamless-scanning projection lithography systems developed by Anvik Corporation (U.S. Pat. Nos. 4,924,257 and 5,285,236) meet both the resolution and alignment requirements for next-generation microelectronic packages—and deliver high throughputs—and are therefore highly attractive for large-volume production of high-end packages.
A massively parallel maskless lithography technology newly developed by Anvik (U.S. Pat. No. 6,312,134) has promising applications for the production of a wide variety of electronic systems, that require only small-to-moderate-volume production of many specialized components, rather than a large volume of a single component; for example, for military missile defense applications, which require large networks of sensor, communication, and networking equipment, but in limited quantities.
Anvik's prior-art maskless lithography system uses a spatial light modulator (SLM) array instead of a Mylar or glass mask. The SLM is a megapixel display device which can be updated at multi-kHz frame rates. The SLM fully removes the need for hard glass masks, eliminating many of the problems associated with the use of masks, including the cost of purchasing and maintaining masks; the cost of lost yield resulting from masks having defects; and the production time that is lost while waiting for delivery of masks from mask houses. These factors can be particularly significant for electronic components manufactured in low volumes, such as many military electronics, where mask-related issues may be the primary influences affecting the price and delivery of the component.
In spite of the above cited advantages of the prior art maskless lithography technology, there is still a need for a more versatile maskless patterning system where the demagnification of the SLM image onto the substrate can be rapidly and easily varied in order to optimize the trade-off between pattern definition and throughput. Such a versatile system would be capable of patterning a large range of feature sizes on a wide variety of substrate materials, over very large areas, the substrate size limited only by the travel range of the scanning stage. In addition, it would be capable of patterning different regions on the same substrate with different resolution and feature sizes.